The sample characteristics affecting longitudinal initial sample attrition in the Korea youth panel survey

2017 ◽  
Vol 28 (2) ◽  
pp. 157-195
Author(s):  
Lee Kyeong-Sang ◽  
Soon-Rae Lee
Keyword(s):  
Panel Survey ◽  
Initial Sample ◽  
Sample Attrition ◽  
Sample Characteristics

Sample Attrition and Cronbach Alpha: A Five-Year Longitudinal Study

1998 ◽  
Vol 82 (3_suppl) ◽  
pp. 1223-1231
Author(s):  
Richard A. Bernardi
Keyword(s):  
New York ◽  
New York City ◽  
Longitudinal Study ◽  
Geographic Location ◽  
Defining Issues Test ◽  
Initial Sample ◽  
Field Sample ◽  
Cronbach Alpha ◽  
Sample Attrition ◽  
Big Six

Conventional wisdom indicates that as attrition in a field sample occurs, the remaining sample becomes more similar, e.g., homogeneous. This narrowing of the differences in the sample will cause a decrease in reliability as measured by Cronbach alpha. The current research is a 5-yr. longitudinal study that involved a group of auditors from five Big Six firms. The initial sample (Bernardi, 1994a) of 494 auditors was followed for a period of five years to assess the effect of attrition on Cronbach alpha for the Defining Issues Test (Rest, 1979a). At the beginning of the research, alpha was .348; however, by the end of Year five, alpha had decreased to .309. When the sample was stratified by sex and geographic location, the data indicate that, while alpha increased for the majority of the sample, it dramatically decreased for women in the New York City Metropolitan area. This study should assist other researchers who are examining data on a longitudinal basis when the sample is presumed to become more similar over time.

Are There Test Administrator Effects in Large-Scale Educational Assessments?

Methodology ◽  
2007 ◽  
Vol 3 (4) ◽  
pp. 149-159 ◽  
Author(s):  
Oliver Lüdtke ◽  
Alexander Robitzsch ◽  
Ulrich Trautwein ◽  
Frauke Kreuter ◽  
Jan Marten Ihme
Keyword(s):  
Large Scale ◽  
International Student ◽  
Student Assessment ◽  
Student Groups ◽  
Mathematics Scores ◽  
International Student Assessment ◽  
Sample Attrition ◽  
Educational Assessments ◽  
Test Administrator ◽  
Practical Implications

Abstract. In large-scale educational assessments such as the Third International Mathematics and Sciences Study (TIMSS) or the Program for International Student Assessment (PISA), sizeable numbers of test administrators (TAs) are needed to conduct the assessment sessions in the participating schools. TA training sessions are run and administration manuals are compiled with the aim of ensuring standardized, comparable, assessment situations in all student groups. To date, however, there has been no empirical investigation of the effectiveness of these standardizing efforts. In the present article, we probe for systematic TA effects on mathematics achievement and sample attrition in a student achievement study. Multilevel analyses for cross-classified data using Markov Chain Monte Carlo (MCMC) procedures were performed to separate the variance that can be attributed to differences between schools from the variance associated with TAs. After controlling for school effects, only a very small, nonsignificant proportion of the variance in mathematics scores and response behavior was attributable to the TAs (< 1%). We discuss practical implications of these findings for the deployment of TAs in educational assessments.

Effects of Psychotherapy on Brain Activation Patterns in Anxiety Disorders

2016 ◽  
Vol 224 (2) ◽  
pp. 62-70 ◽  
Author(s):  
Thomas Straube
Keyword(s):  
Anxiety Disorders ◽  
Neuronal Plasticity ◽  
Functional Neuroimaging ◽  
State Of The Art ◽  
Methodological Issues ◽  
Future Directions ◽  
Activation Patterns ◽  
New Learning ◽  
Analytical Strategies ◽  
Sample Characteristics

Abstract. Psychotherapy is an effective treatment for most mental disorders, including anxiety disorders. Successful psychotherapy implies new learning experiences and therefore neural alterations. With the increasing availability of functional neuroimaging methods, it has become possible to investigate psychotherapeutically induced neuronal plasticity across the whole brain in controlled studies. However, the detectable effects strongly depend on neuroscientific methods, experimental paradigms, analytical strategies, and sample characteristics. This article summarizes the state of the art, discusses current theoretical and methodological issues, and suggests future directions of the research on the neurobiology of psychotherapy in anxiety disorders.

Energetic properties of peat saturated with petroleum products

2020 ◽  
Vol 13 (2) ◽  
pp. 105-109
Author(s):  
E. S. Dremicheva
Keyword(s):  
Crude Oil ◽  
Diesel Fuel ◽  
Energy Use ◽  
Experimental Studies ◽  
Calorific Value ◽  
Petroleum Products ◽  
Ash Content ◽  
Motor Oil ◽  
Initial Sample

This paper presents a method of sorption using peat for elimination of emergency spills of crude oil and petroleum products and the possibility of energy use of oil-saturated peat. The results of assessment of the sorbent capacity of peat are presented, with waste motor oil and diesel fuel chosen as petroleum products. Natural peat has been found to possess sorption properties in relation to petroleum products. The sorbent capacity of peat can be observed from the first minutes of contact with motor oil and diesel fuel, and significantly depends on their viscosity. For the evaluation of thermal properties of peat saturated with petroleum products, experimental studies have been conducted on determination of moisture and ash content of as-fired fuel. It is shown that adsorbed oil increases the moisture and ash content of peat in comparison with the initial sample. Therefore, when intended for energy use, peat saturated with petroleum products is to be subjected to additional drying. Simulation of net calorific value has been performed based on the calorific values of peat and petroleum products with different ratios of petroleum product content in peat and for a saturated peat sample. The obtained results are compared with those of experiments conducted in a calorimetric bomb and recalculated for net calorific value. A satisfactory discrepancy is obtained, which amounts to about 12%. Options have been considered providing for combustion of saturated peat as fuel (burnt per se and combined with a solid fuel) and processing it to produce liquid, gaseous and solid fuels. Peat can be used to solve environmental problems of elimination of emergency spills of crude oil and petroleum products and as an additional resource in solving the problem of finding affordable energy.

Sign in / Sign up

Export Citation Format

Share Document